Disposable ophthalmic/medical apparatus with timed color change indication

ABSTRACT

A disposable ophthalmic or medical apparatus has a portion with a color changeable dye disposed thereon. The dye changes color after being exposed to oxygen for a controlled and predetermined period of time indicating that the apparatus should no longer be used.

CROSS-REFERENCE TO RELATED APPLICATIONS

N/A

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

FIELD OF THE INVENTION

The present invention relates to a disposable, limited or restricted useproduct that can transmit contaminants, and disease to a person or causeinfection if reused or used beyond a recommended period of time and moreparticularly to such an apparatus with a portion having a colorchangeable dye that changes color after being exposed to oxygen for apredetermined period of time indicating that the device should no longerbe used.

BACKGROUND OF THE INVENTION

Many products currently marketed and sold to consumers are designed forlimited use. These products are usually associated with a single event,a restricted time period or restricted access. There are many reasonsfor the need of single use or limited use products.

An example of a single use product is a disposable syringe. Instrumentcontamination and cross infection between patients is an ever presentconcern if the syringe is inadvertently reused. It is a particularconcern in some countries where repeated use of instruments is known totransmit serious diseases such as HIV and hepatitis. Medical andophthalmic devices that must be sterilized such as scalpels ortonometers (for the measurement of a patient's intraocular pressure)body piercing and tattooing instruments used on multiple clients alsogive cause for concern. Needles used in acupuncture offer anotherexample. Decontamination procedures or employment of single-use devicesare methods used to control cross infection, but they rely on personnelawareness, willingness to follow protocol, monitoring and documentation.

The limited use type of product is usually associated with goods thatshould be used for a restricted time period. One example of this type ofproduct is “daily wear” or disposable contact lenses. Contact lenses forrefractive correction or cosmetic purposes require suitable wear andcare regimes in order to maintain good eye health. Non-compliance on thepart of the patient, either through choice or due to lack of education,can injure the eye. Frequent replacement lenses are sometimes worn forlonger than recommended or they may be stored or cleanedinappropriately.

A number of patents have tried to address the requirements for singleuse, limited use, or restricted access products.

U.S. Pat. No. 3,899,295 describes the use of an indicator containing apH sensitive dye applied to the container of a product such as a medicalinstrument. The indicator displays a first color in a normal atmosphere,then following introduction of a basic atmosphere the sensor displays asecond color. The problem with this patent is that the indicator is notdisplaying information relating to the condition of the productcontained within the package. Since the indicator is not incorporatedwithin or fixed onto the product, the information given actually relatesto the container, not its contents. An additional problem with thispatent is that the basic atmosphere in which the product is stored ischlorine gas which is highly reactive to the materials that comprisemany of the products that one could imagine being supplied in a sterilepackage container, such as metal surgical instruments and manypharmaceutical compounds or drugs.

Similarly, U.S. Pat. No. 4,098,577 by the same inventor describes asimilar pH sensitive indicator and two different atmospheric conditions,however that invention describes the indicator change in the presence ofan acidic atmosphere. As described above, the indicator is notincorporated within or fixed onto the product, therefore the informationpresented by the indicator relates to the container, not its contents.

U.S. Pat. No. 4,526,752 presents a tamper resistant package with anindicator means. The invention describes a container which incorporatesan indicator within its structure to display information on whether acontainer has been previously opened. As with other patents, theindicator relates to the condition of the package and not the productcontained in the package.

U.S. Pat. No. 6,790,411 describes a solution based hydrogen peroxideindicator where the solution has a first color in normal atmosphericconditions, then following a sterilization process using hydrogenperoxide, the solution exhibits a second color. One will certainlyrecognize a problem with this technique by considering the case where apackage that has been sterilized with hydrogen peroxide, is subsequentlytampered with, punctured, or otherwise damaged and made non sterile,while the indicator still displays the sterile condition.

U.S. Pat. No. 6,851,808 describes an ophthalmic lens product with anattached indication means that provides the user information relating tothe products condition or previous use. The invention overcomes many ofthe problems with the previously described patents. However, since theindicator means described in the patent uses changes in the product'slight environment as the initiator for the use indication display, andsince variations exist in the lighting environment where the product isused, the use indication can present at a rate that is faster or slowerthan that which is optimally desired.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention the disadvantages of priorlimited use or restricted use products that can harm a person ifimproperly used as discussed above have been overcome. A disposablelimited or restricted use apparatus in accordance with the presentinvention includes a color changeable portion wherein the time that thecolor change occurs is controlled so that it coincides to theapproximate time of the end of one use of a single use apparatus or tothe approximate expiration time for extended but limited or restricteduse apparatus.

More particularly, the apparatus of the present invention with colorchange indication of use or expiration includes a limited or restricteduse apparatus having a portion that comes in contact with bodily fluidsor tissue so as to be susceptible to the transmission of contaminants ordisease to a person or to cause infection or injury. A color changeabledye is disposed directly on a portion of the apparatus, the dye having afirst color upon immediate exposure to oxygen and for a predeterminedtime thereafter and the dye changing color after the predetermined timeto provide a warning indication that the apparatus should no longer beused.

In one embodiment of the present invention, the apparatus may be amedical device such as a disposable syringe wherein the predeterminedperiod of time prior to color change is approximately five minutes. Inanother embodiment, the medical device is a disposable scalpel and thepredetermined period of time before which the dye changes color isgreater than or equal to one-half hour and preferably one hour. In stillanother embodiment, the apparatus is an ophthalmic device such as adisposable tonometer and the predetermined period of time before thecolor change occurs is approximately ten minutes.

In accordance with a further feature of the invention, the position ofthe dye on the device may be such that the device becomes unusable afterthe color change occurs.

In accordance with another feature of the present invention, theapparatus is a contact lens that is intended to be worn by a user suchthat the lens has a peripheral area that extends beyond the pupil and/orthe iris of a user's eye when worn and wherein the contact lens isdisposable such that it is not intended to be used for more than apredetermined period of time. A color changeable dye is disposed on aportion of the peripheral area of the contact lens wherein the dye issomewhat translucent prior to use of the contact lens and the dyechanges to a visible color after the contact lens has been exposed tooxygen for a predetermined period of time indicating that the contactlens should no longer be used. Because the color change indication ofexpiration is in the periphery of the lens, it does not obstruct theoptical zone of the lens. As such, the lens can still be used withoutobstructing vision after the color change occurs. However, a user isdiscouraged from continuing to wear the expired contact lens since thecolor change indication is visible and apparent to others.

These and other advantages and novel features of the present invention,as well as details of an illustrated embodiment thereof will be morefully understood from the following description and the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a syringe in accordance with oneembodiment of the present invention depicting the area of the colorchangeable dye overlying the graduated scale of the syringe;

FIG. 2 is a perspective view of the syringe of FIG. 1 depicting thesyringe after the timed color change occurs;

FIG. 3 is an illustration of an alternative placement of the dye on asyringe;

FIG. 4 is an illustration of the syringe of FIG. 3 with an expirationmessage printed with the color changeable dye which becomes visibleafter a predetermined period of time;

FIG. 5 is a perspective view of the syringe of FIG. 3 contained in apackage to prevent premature actuation of the color changeable dye;

FIG. 6 is a perspective view of a scalpel with the color changeable dyein accordance with another embodiment of the present invention;

FIG. 7 is a perspective view of the scalpel of FIG. 6 with a messageprinted with the color changeable dye which has become visible after apredetermined time;

FIG. 8 is a cross-sectional view of a tonometer contacting a user's eyeand having the color changeable dye disposed on a central area of thetonometer lens through which the clinician looks;

FIG. 9 is a cross-sectional view of the tonometer and eye of FIG. 8 withthe dye providing a color change indication that the tonometer should nolonger be used;

FIG. 10 is a cross-sectional view of a contact lens in accordance withanother embodiment of the present invention on a user's eye;

FIG. 11 is a front perspective view of the contact lens of FIG. 10 withthe dye in peripheral areas of the contact lens;

FIG. 12 is a front perspective view of the contact lens of FIG. 11depicting the dye after color change has occurred to indicate expirationof the lens;

FIG. 13 is an alternative embodiment of the contact lens of FIG. 11; and

FIG. 14 is a cross-sectional view of a package containing the contactlens of FIG. 11 to prevent premature color change.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a color change indication on aproduct provides accurate information or a warning to a user of: prioruse of a single use product or instrument; a reminder that a limited useproduct has reached it's expiration time; or that a product that isrestricted for use has been tampered with. The warning indication isprovided by a dye that changes color in a time controlled manner whereinthe dye is disposed on the product itself by being either printed on theproduct or incorporated within the material forming a portion of theproduct. The product is then subsequently packaged to provide a sterileenvironment for the product or limited access thereto. The internalatmosphere of the package is an inert gas or a vacuum such that thepackage provides a sealed, substantially atmospheric oxygen freeenvironment for the product. When the package is subsequently opened andthe product is exposed to atmospheric oxygen, the dye disposed on theproduct will change from translucent or somewhat translucent, i.e. amilky white or “water white,” to a blue or red color after a period oftime that is controlled by the composition of the dye as discussed indetail below, and that is selected to correspond to the typical time fora single use of a product in the case of single use products or thatcorresponds to the expiration time of the product. The time at which thedye changes color can also be selected so as to indicate that theproduct may have been tampered with.

In accordance with one embodiment of the present invention, as shown inFIG. 1, a disposable syringe 10 includes a graduated scale 12 printedthereon so that the amount of liquid drawn into the syringe can beaccurately measured. In one embodiment, the color changeable dye 14 isprinted over the scale. In this embodiment, the dye is substantiallytranslucent so that the scale is clearly visible until the dye 14changes color, as depicted at 14′ in FIG. 2, after a predetermined timeassociated with the time of typical use of the single use disposablesyringe 10.

For single use disposable products where the dye is required to besubstantially translucent and wherein the dye is to change color afterexposure to oxygen after five to ten minutes, the dye solution may beformed as follows. Approximately 12 grams of glucose is added to 600 ccof distilled de-ionized water. Next, approximately 12 grams of sodiumhydroxide is added to the mixture. To this mixture is added 10 cc of aMethylene Blue solution prepared by mixing 0.1 gram of Methylene Blue in100 cc of ethanol where the ethanol evaporates in the drying process.Thereafter, 60 grams of methyl cellulose is added to the mixture.Alternatively, E414 acacia gum may be substituted for the methylcellulose. This dye solution will change from translucent to blue in ashort amount of time after the package is opened and the product onwhich the dye is disposed is exposed to oxygen. If the color changedesired is from substantially translucent to a red color, 10 cc of aSafranine T solution can be substituted for the Methylene Blue solution.The Safranine T solution is prepared by mixing 0.3 grams of Safranine Twith 10 ml of ethanol.

In order to delay the time at which the dye changes color upon exposureto oxygen, Iron (II) carbonate can be added to the above dye solution.For example, 0.1 grams of Iron (II) carbonate can be added to a 3 mlquantity of the above dye solution forms a dye that will change color toeither blue or red after approximately nine or ten minutes. Byincreasing or decreasing the amount of Iron (II) carbonate the time thatit takes for the color change to occur upon exposure to oxygen can berespectively increased or decreased. It is noted that, the addition ofthe Iron (II) carbonate will change the dye from being substantiallytranslucent to somewhat translucent or a faint, milky white known as“water white” wherein the translucency diminishes as more Iron (II)carbonate is added.

In a preferred embodiment of the disposable syringe, a dye is employedthat remains translucent or somewhat translucent for a period ofapproximately five minutes, the typical time of a single use of thedisposable syringe. In the embodiment of the syringe depicted in FIGS. 1and 2, because the dye is disposed over the graduated scale, when thetime controlled color change occurs, the graduated scale is no longerclearly visible so that the disposable syringe cannot be accidentallyreused. In this manner, the transmission of contaminants or disease fromone patient to another by an inadvertent reuse of the syringe isprevented.

In another embodiment of the present invention as depicted in FIGS. 3and 4, the dye is disposed on another area such as 18 of the disposablesyringe 10. The dye can be used as an ink to print a message on thedisposable product so that when the color change occurs the message,such as the word “USED,” becomes visible to the user as shown at 18′ inFIG. 4. The dye of the present invention dries quickly after placed onthe product. After it is dry, the product can be sterilized with anycommon, low temperature sterilization technique and then placed in asealed container or package 16, as depicted in FIG. 5, with an internalatmosphere of an inert gas or a vacuum. In the sealed, substantiallyatmospheric oxygen free package, the ink will remain translucent or“water white”. When the package is subsequently opened and the productis exposed to atmospheric oxygen, the dye disposed on the product willchange from substantially translucent or “water white” to blue or redafter five or ten minutes depending upon the amount of Iron (II)carbonate in the solution.

If it is desired that the color change takes substantially longer thanten minutes, for example, twelve to sixteen hours, 0.5 grams of Iron(II) carbonate is added to a 3 ml quantity of the dye solution insteadof 0.1 grams of Iron (II) carbonate. It is noted that the Iron (II)carbonate acts as an oxygen scavenger in the dye solution thatpreferentially absorbs oxygen, converting to Iron (III) carbonate. Whenthe Iron (II) carbonate is completely converted to Iron (III) carbonate,the oxygen in the environment reacts with the color changeable dye sothat the dye changes to blue or red and becomes visible.

In order to prevent the dye from changing color until an even longertime has passed, wax can be added to the dye solution. To provide acolor change indication on a product after approximately 1500 hours orabout two months, the oxygen diffusion rate through the dye solution canbe lowered or decreased by the addition of wax as follows. Specifically,when 0.3 cc of beeswax is added to a 3 ml quantity of the dye describedabove, the color change is delayed by approximately ten hours for avolume of dye of 0.01 mm3. This amount of dye can be used in an area ofapproximately 2 mm in height and 20 mm long on a product. With theaddition of 0.6 cc beeswax to the dye solution, the color change can bedelayed to approximately 100 hours. To further extend the time that ittakes for the color change to 1500 hours, 0.7 grams of Iron (II)carbonate can be added to the dye solution and wax mixture. It is notedthat if too much wax is added to the dye, the quality of printing textcan decrease.

In another embodiment of the present invention as depicted in FIG. 6, adisposable scalpel 24 has the dye 26 of the present invention disposedthereon in an area that will be clearly visible to the surgeon when thedye changes color. As depicted in FIG. 7, a warning message 28 may beprinted with the dye on the scalpel to inform the surgeon that thescalpel has been “USED” wherein the color change occurs after at leastone-half hour and preferably one hour after the scalpel is removed froma substantially oxygen free package or container as discussed above withrespect to the syringe. In this way, the surgeon is warned that thescalpel should not be inadvertently used again but should be disposedof.

An ophthalmic device that incorporates the present invention is depictedin FIGS. 8 and 9. Specifically, FIG. 8 illustrates a tonometer 29 thatis used in contact with a patient's eyes 30. In ophthalmology, variousprocedures require a lens or instrument that contacts a patient's eye. Atonometer is one such device which includes a lens 31 which, for adisposable tonometer, may be formed of optical quality acrylic, forexample. The lens 31 has a surface 33 through which a clinician viewsthe eye 30 when the tonometer 29 is mounted on a slit lamp. Thetonometer 29 also includes a holder 29 which is used to mount thetonometer onto the slit lamp. For a disposable tonometer, the holder 29can be formed of plastic for example. In accordance with one embodiment,the dye 32 of the present invention can be disposed on a central area ofthe lens 31 of the tonometer. Since the typical time of use of thedisposable tonometer 29 of the present invention is very short, the dye32 can be of a formulation that is substantially translucent and doesnot change color for approximately five to ten minutes. After that time,when the dye changes color to blue or red, the dye prevents inadvertentreuse of the disposable tonometer by blocking the visual path in thetonometer to the patient's eye. Thus, the inadvertent transmission ofcontaminants or diseases from one patient to another patient via contactof a reused ophthalmic device with the patient's eyes is prevented. Inanother embodiment of the present invention, the dye can be disposed toform a ring or other symbol on the surface 33 of the tonometer lens 31or the dye can be disposed on the holder of the tonometer 36.

A problem that has arisen in ophthalmology with refractive contact lensuse such as “daily wear” or “monthly wear” disposable contact lenses isthat the user of the contact lens does not dispose of the contact lensat the recommended time but wears the contact lens longer than they aresupposed to. This however can damage the eye. The contact lens of thepresent invention as depicted in FIGS. 10-14 overcomes this problem byproviding a visual indication on the contact lens itself that thecontact lens should be removed from the eye after the contact lens hasbeen worn for the prescribed amount of time.

As shown in FIG. 10, a refractive contact lens 40 is worn on a cornea 36of an eye 30. Light 44 entering the person's cornea is correctly focusedby the contact lens 13 onto the retina at a point 45. The clear opticalpath of the light 44 intersects the central portion of the contact lensin the optical zone 48 of the eye and or lens. The periphery 43 of thecontact lens 40 as shown in FIGS. 10-13, however extends beyond theoptical zone 48 of the user's eye such that when the contact lens isworn, the peripheral area of the contact lens extends beyond the pupiland/or iris of a user's eye so that it overlies the iris and/or thesclera.

In accordance with the present invention, the color changeable dye 46 asdescribed above is disposed on a portion of the peripheral area of thecontact lens. The formulation for the dye is preferably that whichdelays the color change of the dye for approximately twelve to sixteenhours, or longer, according to the longest time that the contact lensmanufacturer suggests that the contact lenses should be worn. Becausethe formulation for the dye for twelve to sixteen hours includes Iron(II) carbonate, prior to the color change, the dye is milky white or“water white”. However, when the dye is disposed in one or more areassuch as 46 and 47 in the periphery 43 of the contact lens 40, when thecontact lens is worn by the user the area in which the dye is placed onthe contact lens overlies the iris and/or the sclera and is not visibleto an observer. As discussed above for the other devices, the contactlens 40 should be placed in a substantially atmospheric oxygen freepackage 50 as shown in FIG. 14. A user of the contact lens 40 removesthe contact lens from the package for immediate use in the eye. Afterthe contact lens has been worn in the eye for the recommended time bythe manufacturer, the color change of the dye occurs as depicted in FIG.12 wherein, dark blue or dark red spots are clearly visible in theperiphery of the contact lens by an observer looking into the contactlens wearer's eye. As such, the contact lens wearer is encouraged toremove the contact lens from his eye and dispose of it as recommended.However, because the dye is disposed in the periphery of the contactlens outside of the optical zone 48, the dye, after it changes colordoes not impair the vision of the user. As such, in emergencies, thecontact lens can be continued to be worn after the color change occurswithout visual impairment. However, the user is discouraged from wearingthe lens beyond its recommended use time since the die spots or ringwill be readily apparent by anyone looking at the contact lens wearer'seye.

FIG. 13 illustrates another embodiment of the positioning of the dye toform portions of a ring or a continuous ring in the periphery 43 of thecontact lens outside the optical zone 48.

The present invention has much wider applications than have beendescribed herein. For example, the dye of the present invention can beused on cosmetic applicators that are stored with the cosmetic itselfsuch as mascara or eyeliner. It has been found that although suchcosmetics include preservatives to slow the growth of bacteria that caninfect the eye, these preservatives have a limited life so thatreplacement of cosmetics is recommended by doctors every three to sixmonths. The cosmetics however do not have an expiration date on theproduct or the package. The dye of the present invention can be appliedto the handle of a mascara applicator or eyeliner applicator, forexample, so that a warning message becomes visible at the recommendedtime of replacement. As such a user is warned that the cosmetic shouldbe disposed of prior to the expiration of the preservative to preventeye infections. The present invention is also applicable to oralmedications such as pills wherein the dye is printed directly onto thepill and changes color from white or translucent to another darker coloror warning symbol when the environmental oxygen level around the pillchanges. If the pills are individually packaged, the color changeindication can occur quickly after opening the package so as to providea tamper indication. Alternatively, if multiple pills are contained in abottle or the like, the color change indication of the dye should betimed to coincide with the expiration of the pills. It is noted that inpreparing the, Methylene Blue solution, instead of ethanol, another typeof alcohol can be used wherein the alcohol evaporates on the pill in thedrying process.

Many further modifications and variations of the present invention arepossible in light of the above teachings. Thus, it is to be understoodthat, within the scope of the appended claims, the invention may bepracticed otherwise than as described hereinabove.

What is claimed and desired to be secured by Letters Patent is: 1-67.(canceled)
 68. An apparatus with time controlled color change indicationcomprising: an apparatus that includes a disposable, limited orrestricted use product; an oxygen sensing color changeable dye disposedon the apparatus, the dye being translucent or having a first color uponapplication and the dye changing color after exposure to atmosphericoxygen for a defined time wherein the dye indicates the condition of thedisposable, limited or restricted use product.
 69. An apparatus asrecited in claim 68 wherein the dye comprises at least Methylene Blue,glucose, and sodium hydroxide.
 70. An apparatus as recited in claim 68wherein the dye comprises at least Safranine T, glucose and sodiumhydroxide.
 71. An apparatus as recited in claim 68 wherein the dyecomprises at least Methylene Blue, glucose, sodium hydroxide, and Iron(II) carbonate.
 72. An apparatus as recited in claim 68 wherein the dyecomprises at least Safranine T, glucose, sodium hydroxide and Iron (II)carbonate.
 73. An apparatus as recited in claim 68 wherein the dyecomprises at least Methylene Blue and wax.
 74. An apparatus as recitedin claim 68 wherein the dye comprises at least Safranine T and wax. 75.An apparatus as recited in claim 68 wherein the dye comprises at leastMethylene Blue, wax and Iron (II) carbonate.
 76. An apparatus as recitedin claim 68 wherein the dye comprises at least Safranine T, wax and Iron(II) carbonate.
 77. An apparatus as recited in claim 68 wherein the dyecomprises at least glucose, sodium hydroxide, Methylene Blue orSafranine T, and methyl cellulose or acacia gum.
 78. An apparatus asrecited in claim 68 wherein the dye comprises at least Methylene Blueand Iron (II) carbonate.
 79. An apparatus as recited in claim 68 whereinthe dye comprises at least Safranine T and Iron (II) carbonate.